What's more, researchers found blood pressure tests may not always be accurate among young people, or consistent from one reading to the next.
"At this point, the jury is out. We just don't know if this is worth doing or not," said Dr. Matthew Thompson, who led the new research at Oxford University in the UK.
"We desperately need research on how to diagnose kids with high blood pressure, which kids should be treated and what are the most effective treatments."
Thompson said although most U.S. children have their blood pressure measured at routine checkups, those readings are never taken on healthy kids in the UK.
His team reviewed the latest evidence on childhood blood pressure tests for the government-backed U.S. Preventive Services Task Force.
Thompson and his colleagues analyzed 34 studies covering diagnosis, treatment and long-term effects of high blood pressure in kids and teens. None of those answered the researchers' central question - whether screening can help prevent or delay cardiovascular disease in adults.
Accuracy of blood pressure readings from one measurement to the next was "modest at best," according to Thompson.
"The false positive rate means that most children who screen positive won't actually have high blood pressure," he told Reuters Health.
Among studies that tracked children and teens over time, researchers found anywhere from 19 to 65 percent of youth with high blood pressure also had hypertension as adults.
Seven studies tested seven different drugs for kids with hypertension and found they typically weren't any better at lowering blood pressure than a drug-free placebo pill. But those studies lasted only a few weeks - and children with hypertension would likely take the drugs for years.
"That's really not good enough evidence to know if they're effective and safe for decades," Thompson said.
Programs aiming to change young people's lifestyle, such as by encouraging them to be more active or eat less salt, also didn't have a clear effect, the researchers wrote this week in Pediatrics.
PART OF STANDARD CARE'
Based on the findings, the Task Force concluded in a draft recommendation that there isn't enough evidence to balance the benefits and harms of screening young people to prevent future disease.
The draft is available online for public comment for the next month here: http://bit.ly/uRZqMF.
The U.S. National Heart, Lung, and Blood Institute recommends all children routinely get their blood pressure measured. But another recent review also concluded there isn't enough evidence to support blood pressure checks for kids, further stoking controversy on the issue (see Reuters Health story of Jan 7, 2013 here: http://reut.rs/V5FY63.)
Dr. Bonita Falkner, a pediatrician at Thomas Jefferson University in Philadelphia who has studied hypertension, said she doesn't think the findings should change practice.
"It remains unknown how much hypertension in childhood contributes to (adult high blood pressure), but there is evidence it begins in childhood," Falkner, who wasn't involved in the review, told Reuters Health.
The researchers agreed there's a need for more studies to address the information gaps related to childhood blood pressure checks.
"It's been recommended for some time now that pediatricians measure blood pressure in children, starting at age three, as part of routine health assessments," she said. "It's pretty much become part of standard care."
Thompson said until more research is done, it's unclear what the right answer is on blood pressure checks for youth.
"To me, the evidence shows that it's not clear that screening or not screening is good or bad," he said.
SOURCE: http://bit.ly/WtBzqF Pediatrics, online February 25, 2013.